Hydrofoil attachment for boats



Sept- 29, 1964 F. T. lRGENs 3,150,626

' HYDRoFoIL. ATTACHMENT FOR BoATs Filed OCT.. 25, 1962 2 Sheets-Sheet l IN VEN TOR.

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Sept. 29, 1964 F. T. IRGENS HYnRoFoTr. ATTACHMENT FOR BoATs 2 Sheets-Sheet 2 Filed Oct. 23, 1962 E u mw @I HH n.1..." @nu T 'g 22; v 2/ L Y j (UTI 56. /rraz/va/L United States Patent O 3,150,626 HYDROFOIL ATTACHMENT FOR BOATS Finn T. Irgens, Milwaulree, Wis., assignor to Outboard Marine Corporation, Waukegan, Ill., a corporation of Delaware Filed Oct. 23, 1962, Ser. No. 232,465 18 Claims. (Cl. 114-665) The invention relates generally to hydrofoil devices or attachments for boats. The invention provides a hydrofoil device for a boat including a U-shaped frame or cradle which supports a pair of hydrofoil sections and which includes a cross member or stern board capable of supporting a propulsion device, such as an outboard motor.

The invention also provides the combination of a hydrofoil device including a frame and a pair of hydrofoil sections, together with Ia boat, and controllable means for vertically displacing the boat relative to the connected hydrofoil sections. With such an arrangement, the frame can be located at a generally predetermined distance above the surface of the water, regardless of whether the boat is hydroplaning or traveling through the water without hydroplaning. The capacity for retaining the frame at a given height above the surface of the water permits support of a propulsion device on the frame so as to provide for operation of the propeller at a proper, generally constant depth in the water.

In one embodiment, the invention also provides for incorporation in the boat hull of wells or recesses and/ or steps, and for shaping the hydrofoil sections so as to be receivable relative to the recesses or steps to provide a smooth transition between the undersurface of the hull and the undersurface of the associated hydrofoil section, at least `in the area which is submerged during conventional operation of the boat.

Other objects and advantages of the invention will become known by reference to the following description and the accompanying drawings wherein:

FIGURE 1 is a side elevational view of one embodiment of a boat 11 which embodies various of the features of the invention and which is equipped with a hydrofoil structure 13;

FIGURE 2 is a view similar to FIGURE 1 showing the boat hull in its hydroplaning disposition;

FIGURE 3 is a plane view of the boat shown in FIG- URES 1 and 2;

FIGURE 4 is a view similar to FIGURE 1, with certain parts omitted and with certain parts in section, showing an altern-ate nesting arrangement of the hydrofoil structure with respect to the boat hull;

FIGURE 5 is a view similar to FIGURE 4 showing an alternate arrangement for lowering the hydrofoil structure;

FIGURE 6 is a sectional view taken generally along line 6 6 of FIGURE 5;

FIGURE 7 is a sectional view taken generally along line 7-7 of FIGURE 5;

FIGURE 8 is a view similar to FIGURE 5 showing the boat hull in hydroplaning disposition;

FIGURE 9 is an enlarged view, partially in section, of one arrangement for nesting a hydrofoil section with respect to a boat hull;

FIGURE 10 is an enlarged view, partially in section, of another arrangement for nesting a hydrofoil section with respect to a boat hull; and

FIGURE 11 is an enlarged view, partially in section, of still another arrangement for nesting a hydrofoil section relative to a boat hull.

The boat 11 shown in FIGURE 1 is exemplary of various forms of V bottom boats which can be employed in accordance with the invention. The boat 11 includes a 3,156,626 Patented Sept. 29, 1964 ice hull 15 which is generally of conventional construction, except as noted hereinafter, and which is usable with or without the hydrofoil attachment 13. As shown, the boat hull 15 is associated with the hydrofoil structure or attachment 13, which hydrofoil attachment is connected to the boat hull 15 by suitable means 17 for effecting vertical relative displacement between the boat hull 15 and the hydrofoil structure 13.

The hydrofoil structure 13 comprises a frame or cradle 19 which supports a pair of generally parallel, transversely extending hydrofoil sections 21 and 22 which are of generally similar construction and which are respectively spaced fore and aft with respect to the boat hull 15. Each of the hydrofoil sections 21 and 22 is V-shaped in athwart-ship cross section and has a longitudinal or fore and aft section of foil shape to effect the creation of lift incident to travel through a iluid medium, such as water.

The frame 19 is generally U-shaped and comprises a pair of side members or rails 23 which extend in generally parallel relation to the sides of the boat hull 15 and a cross member or stern board 25 which connects the side rails 23 and serves as a support for a marine propulsion device, such as the outboard motor 27 shown in the drawings. Use of a U-shaped frame including the transverse stern board 25 permits mounting of the propulsion unit on the hydrofoil structure 13 rather than on the boat transom.

As also shown in FIGURES 1 and 2, the frame 19 additionally includes vertically extending portions 29 which can be considered part of the side rails 23 and to which the hydrofoil sections 21 and 22 are xedly united. The fore and aft spacing of the hydrofoil sections 21 and 22 can be varied as desired to obtain particular boat trim and steering characteristics. However, the boat hull 15 and hydrofoil sections 21 and 22 are desirably related in construction so that resistance to travel of the boat during non-planing movement through the water is at a minimum.

Specicially, in the preferred construction, the boat hull 15 incorporates on its underside a pair of recesses 31'and 33 for rsepectively receiving the hydrofoil sections 21 and 22.

Recess 31 is dimensioned to permit receipt of substantially all of the associated hydrofoil section 21, as shown best in FIGURE 9, while recess 33, located adjacent to the transom of the boat hull 15, is adapted to receive only the forward part of the hydrofoil section 22, in a manner such as shown partially in dotted outline in FIG- URE 10. Both recesses 31 `and 33 are also dimensioned, so that when the hydrofoil sections 21 and 22 are received therein, the bottoms of the hydrofoil sections 21 and 22 merge smoothly with at least the rearward edge of the forwardly adjacent undersurface of the boat hull. Thus, during non-planing operation, the presence of the hydrofoil sections does not add to resistance to travel of the boat hull through the water either by reason of a substantial or material interruption in the smoothness of the undersurface of the boat hull or by a material increase in wetted area.

In FIGURE 4, a hydrofoil structure substantially similar tothe hydrofoil structure 13 is shown utilized with a slightly modified hull including a step 135. Consistent with load factors, trim, and steering characteristics, the forward hydrofoil section 121 can extend aft from the vertical step in a recess 137a (see FIG. ll) defined, at least in part, by the Step 135. Alternatively, the hydrofoil section 121 can extend in a recess 137b (see FIGS. 4 and l0), extending at least partially forwardly of the step 135. If desirable because of load factors, trim, or steering characteristics, the after hydrofoil section 122 can extend wholly within a recess 133 (see FIG. 4), as in a manner such as shown in FIGURE 9, or can extend from aft of the recess 133 beyond the boat transom 139 in a manner such as shown in FIGURE l and as indicated in FIGURE in dotted outline. Use of a hydrofoil section extending partially aft from the boat hull permits wider latitude in the fore and aft positioning of the hydrofoil sections with minimum increase in friction due to increased wetted area.

Various arrangements can be employed for raising and lowering the boat hull relative to the hydrofoil structure. In the embodiment shown in FIGURES 1 through 4, the U-shaped frame 19 and the boat hull 15 are displaced vertically relative to each other by means in the form of a mechanism which is primarily boat mounted and which includes at least a pair of means or levers 51 pivotally connected to the frame 19, means for pivotally supporting respective ones of said levers on each of the sides of said boat hull 15, and means for oscillating said levers 51, whereby relative vertical movement between the frame 19 and the boat hull 15 is provided incident to pivotal movement of said levers.

More particularly, in FIGURES l through 4, a pair of rockshafts 53 are rotatably supported by the boat hull 15 and project, at each end, outwardly of the boat hull. Secured to one pair of adjacent rockshaft ends are respective bell cranks 55, one arm 57 of each bell crank 55 providing one of the before mentioned levers. The arms 57 are pivotally secured at their outer ends to the frame 19. Fixedly mounted at the other ends of the rockshafts 53 are respective links or lever arms 59 which are pivotally connected at their outer ends to the frame 19. The rockshafts 53 effect common pivotal movement of the arms 57 and links 59. The rockshafts 53 are located relative to the boat hull and the arms 57 and the links 59 are dimensioned and pivotally connected to the frame in the area generally above the hydrofoil sections so that, during relative displacement between the boat hull and the frame, the arms 57 and links 59 move pivotally relative to the boat hull through arcs located rearwardly of the respectively associated rockshafts. This configuration also makes provision so that the fore and aft relation of the hydrofoil sections to the boat hull, when the boat hull is in its uppermost position, corresponds generally to the position of the hydrofoil sections when the hydrofoil structure is in nested relation to the boat hull.

Although various arrangements can be used to pivot or oscillate the rockshafts 53, in the particular construction illustrated in FIGS. 1 through 4, the rockshaft oscillating means comprises a motor in the form of a hydraulic ram 61 which is mounted on the boat hull 15 and which is connected to an actuating rod 63 in a manner permitting vertical lost motion. In turn, the actuating rod 63 is connected at its ends to the outer ends of the other arms 65 of the bell cranks 55. Actuation of the hydraulic ram 61 causes fore and aft movement of the actuating rod 63, thereby pivoting the rockshafts 53.

The connection of the hydraulic ram 61 to the frame 19 can include means for resiliently supporting the frame to provide a shock absorbing feature. In the illustrated construction, the hydraulic ram is joined to the rod 63 by a connection slideable relative to the rod. More specically, the piston 67 of the hydraulic ram 61 is connected to a sleeve member 69 which is axially slideable on the actuating rod 63 between a pair of collars 71 fixed in axial spaced relation on the actuating rod 63. The sleeve member 69 is normally retained in centered position between the collars 71 by a pair of oppositely acting helical compression springs 73 which are respectively carried in encircling relation to the actuating rod between the sleeve member and the respective collars and which, under normal conditions, are precompressed.

In the embodiment shown in FIGS. 5 through 8, the vertical displacement means is principally carried on the U-shaped frame 19. More particularly, the frame 19 and the boat hull 15 are displaced vertically relative to each other by a rack and pinion arrangement carried on each side of the boat hull. More specifically, one or more racks 79 extend along respectively generally vertical parts of the exterior of each side of the boat hull 15 and a cooperating pinion or pinions 31 are carried in respective meshing engagement with the racks 79 by respective shafts 33 mounted on the frame 19. The pinion or pinions 81 on the opposite sides of the frame 19 are rotated in unison by suitable means including extension of the pinion carrying shafts 83 aft to adjacent the cross member 25. Carried at the ends of each of the shafts 33 is a sprocket S5 in meshing engagement with a chain 86. In turn, each of the chains 86 is meshed around a sprocket 87 mounted on the cross member 25. Rotatably connected with one of the sprockets 87 is a pinion enmeshed with a pinion part of a sprocket Wheel @9 rotatably carried by the cross member 25.

Trained about the sprocket wheel 89 is a link chain 91 which is also trained about a second sprocket wheel 93 rotatably connected with the other sprocket 87. As a result, displacement transversely of the frame 19 of one of the links of the chain 91 results in opposite rotation of the shafts 83 and pinions 81 carried thereon, thereby causing common linear movement of the pinions 31 relative to the racks 79.

Transverse displacement of the link chain 91 to obtain vertical displacement of the boat hull 15 relative to the frame 19 is effected by a motor, such as a hydraulic ram 95. The ram 95 is mounted on the cross member 25 with its axis in parallel relation to one run of the chain 91 and includes a piston rod 97 connected to one of the links of the chain 91.

Power for effecting vertical displacement of the boat hull 15 rela-tive ot the frame 19 can be supplied in various arrangements. When a hydraulic ram is used, power can be supplied to the ram by an arrangement similar to that disclosed in the co-pending application, Serial No. 154,420, assigned to the assignee of this application.

Various of the features of the invention are set forth in the following claims.

What is claimed is:

1. The combination of a boat hull, a hydrofoil attachment comprising a frame including a pair of side rails extending in generally parallel relation to and along the sides of said boat hull, and a cross member joining said side rails and disposed rearwardly of the stern of said boat hull, and a pair of hydrofoil sections joined to said side rails in depending transverse relation thereto and in generally parallel relation to each other, and means connecting said boat hull to said frame for vertically displacing said boat hull relative to said hydrofoil attachment.

2. A combination in accordance with claim 1 wherein said Vertical displacement means includes a lever arm, means pivotally connecting said lever arm to said boat hull and to said frame, and power operated means drivingly connected to said lever arm for rotating said lever arm about one of its pivotal connections.

3. The combination of a boat hull, a hydrofoil attachment comprising a frame including a pair of side rails extending in generally parallel relation to and along the sides of said boat hull, and a cross member joining said side rails and disposed rearwardly of the stern of said boat hull, and a pair of hydrofoil sections joined to said side rails in transverse relation thereto and in generally parallel relation to each other, a pair of bellcrank levers on one side of said boat hull, each bellcrank lever having a pair of lever arms, a second pair of levers on the other side of said boat hull, a pair of transverse rock shafts rotatably journalled on said boat hull with the ends thereof extending exteriorly of said boat hull, means respectively pivotally connecting said bellcrank levers intermediate said lever arms to adjacent ones of the ends of said rock shafts, means respectively pivotally connecting one end of each of said second pair of levers to the other ends of said rock shafts, means respectively mounting one lever arm of each of said bellcrank levers to said frame, means respectively mounting the other end of each of said second pair of levers to said frame, a rod connected to the ends of the other lever arms of each of said bellcrank levers, and means for shifting said rod fore and aft to rock said lever arms relative to said boat hull.

4. A combination in accordance with claim 1 wherein said vertical displacement means includes a rack on one of said frame and said boat hull, and a pinion on the other of said frame and said boat hull, and power operated means connected to said pinion for rotation thereof.

5. A combination in accordance with claim l wherein said vertical displacement means includes a vertically extending rack on each side of said boat hull, a pinion rotatably carried on each of said side rails in respective engagement with said racks, and power operated means on said frame and connectedto said pinions for eifecting opposite rotation of said pinions to effect raising and lowering of said boat hull relative to said frame.

6. A combination in accordance with claim 5 wherein said power operated means is a hydraulic ram.

7. A combination in accordance with claim 1 wherein said vertical displacement means includes resilient, shockabsorbing means.

8. The combination of a boat hull, a hydrofoil attachment comprising a U-shaped frame including a pair of side rails extending in generally parallel relation to and along the sides of said boat hull, and a cross member joining said side rails and disposed rearwardly of the stern of said boat hull, and a pair of hydrofoil sections joined to said side rails in depending transverse relation thereto and in generally parallel relation to each other, means connecting said boat hull to said U-shaped frame for vertically displacing said boat hull relative to said hydrofoil attachment, and a marine propulsion device supported on said cross member.

9. The combination of a boat hull having on its undersurface a pair of spaced, generally parallel, transversely extending recesses, a hydrofoil attachment comprising a U-shaped frame including a pair of side rails extending in generally parallel relation to and along the sides of said boat hull, and a cross member joining said side rails and disposed rearwardly of the stern of said boat hull, and a pair of hydrofoil sections joined to said side rails in transverse relation thereto and in generally parallel relation to each other, said hydrofoil sections having portions dimensioned to be received in said recesses and, when in said recesses, to be in generally coplanar relation to the portions of said undersurface around the margins of said recesses, and means connecting said boat hull -to said U-shaped frame for vertically displacing said boat hull relative to said hydrofoil attachment to and from between a lirst disposition with said hydrofoil sections received in said recesses and a second disposition with the undersurface of said boat hull in vertically spaced relation to said hydrofoil sections.

10. The combination of a hydrofoil attachment comprising a frame including a pair of side rails extending in generally parallel relation to and along the sides of said boat hull, and a cross member joining said side rails rearwardly of the stern of said boat hull, and a pair of hydrofoil sections joined to said side rails in transverse relation thereto and in generally parallel relation to each other, a boat hull having on its undersurface a step with a vertical dimension greater than the maximum vertical dimension of one of said hydrofoil sections, and a recess with a maximum vertical dimension at least as large as the maximum vertical dimension of the other of said hydrofoil sections and having a shape generally conforming to the upper portion of the transverse outline of the other of said hydrofoil sections, and mean-s connecting said boat hull to said frame for vertically displacing said boat hull relative to said hydrofoil attachment to and from a rst'disposition with said one hydrofoil section located immediately after said step and above the undersurface of said hull immediately forwardly of said step andwith the other of said hydrofoil sections substantially within said recess to present a generally unbroken transition between the undersides of said hydrofoil sections andV of said hull and a second disposition with the undersurface of said boat hull in vertically spaced relation to said hydrofoil sections.

11. The combination of a boat hull having on its undersurface a step, a hydrofoil attachment including a U-shaped frame including a pair of generally parallel side rails, and a pair of hydrofoil sections joined to said side rails in depending relation thereto, one of said hydrofoil sections having a maximum vertical dimension less than the vertical dimension of said step, and means mounting said hydrofoil attachment on said boat hull for relative vertical movement between said boat hull and said hydrofoil attachment relative to a position wherein said one hydrofoil section and said boat hull are in closely adjacent relation, said one hydrofoil section being located, when said hydrofoil attachment is in said position, immediately aft of said step with the lower surface of said one hydrofoil section disposed above the undersurface of said hull immediately forwardly of said step.

12. The combination of a boat hull having on its undersurface a step, a hydrofoil attachment including a U- shaped frame including a pair of generally parallel side rails, and a pair of hydrofoil sections joined to said side rails in depending relation thereto, one of said hydrofoil sections having a maximum vertical dimension less than the vertical dimension of said step, and means mounting said hydrofoil attachment on said boat hull for relative vertical movement between said boat hull and said hydrofoil attachment relative to a position wherein said one hydrofoil section and said boat hull are in closely adjacent relation, and said one hydrofoil section being located, when said hydrofoil attachment is in said position, at least partially aft of said step and so that the undersurface of said one hydrofoil section constitutes a smoothly extending continuation of the portion of the undersurface of said hull extending immediately forwardly of said one hydrofoil section.

13. A hydrofoil attachment for a boat comprising a pair of spaced side rails, a transverse member joining adjacent ends of said side rails and adapted to support a marine propulsion unit, and a pair of spaced, generally parallel hydrofoil sections depending from said side rails and extending transversely thereof.

14. A hydrofoil attachment in accordance with claim 13 including a pinion rotatably carried on each of said side rails, power operated means on said frame and connected to said pinions for efecting opposite rotation of said pinions.

15. A hydrofoil attachment in accordance with claim 14 wherein said power operated means is a hydraulic ram.

16. A hydrofoil attachment for a boat comprising a frame including a pair of spaced side rails, and a transverse member joining adjacent ends of said side rails a pair of spaced generally parallel hydrofoil sections depending frorn said side rails and extending transversely thereof, and means connected to said frame and adapted for mounting said frame to a boat hull for movement between two positions of said boat hull relative to said frame, said mounting means including power means for eifecting relative displacement of said frame and said boat hull between said two positions.

17. A hydrofoil attachment in accordance with claim 16 wherein said power operated means includes a motor mounted on said frame.

18. The combination of a boat hull, a hydrofoil attachment comprising a frame including a pair of side rails extending in generally parallel relation to and along the sides of said boat hull, and a cross member joining said side rails and disposed rearwardly of the stern of said boat hull, and a pair` of hydrofoil sections joined to said side rails in transverse relation thereto and in generally parallel relation to each other, a pair of bellcrank levers on one side of said boat hull, each bellcrank lever having a pair of lever arms, a second pair of levers on the other side of said boat hull, a pair of transverse rock shafts rotatably journalled on said boat hull with the ends thereof extending exteriorly of saidv means respectively mounting one lever armof each ofv said bellcrank levers to said frame, means respectively mounting the other end of each of said second pair of levers to said frame, a rod connected to the ends of the other lever arms of each of said bellcrank levers, a

8, pair of collars fixed in axially spaced relation on said rod, a hydraulic motor including a piston having an axially slideable connection on said rod between said collars, and helical spring means encircling said rods between isaid slideable connection and each of said collars.

References Cited in the le of this patent UNITED STATES PATENTS 1,296,876 Tarbox Mar. 11, 1919 1,779,075 Plum Oct. 21, 1930 2,214,945 Weihmiller Sept. 17, 1940 2,646,235 Dawson July 21, 1953 2,991,747 Bader et al. July 11, 1961 3,013,515 Morel Dec. 19, 1961 FOREIGN PATENTS 553,450 Great Britain May 21, 1943 867,965 France Sept. 8, 1941 

1. THE COMBINATION OF A BOAT HULL, A HYDROFOIL ATTACHMENT COMPRISING A FRAME INCLUDING A PAIR OF SIDE RAILS EXTENDING IN GENERALLY PARALLEL RELATION TO AND ALONG THE SIDES OF SAID BOAT HULL, AND A CROSS MEMBER JOINING SAID SIDE RAILS AND DISPOSED REARWARDLY OF THE STERN OF SAID BOAT HULL, AND A PAIR OF HYDROFOIL SECTIONS JOINED TO SAID SIDE RAILS IN DEPENDING TRANSVERSE RELATION THERETO AND IN GENERALLY PARALLEL RELATION TO EACH OTHER, AND MEANS CONNECTING SAID BOAT HULL TO SAID FRAME FOR VERTICALLY DISPLACING SAID BOAT HULL RELATIVE TO SAID HYDROFOIL ATTACHMENT. 